Table of contents
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Fever Background
- Regulated by anterior hypothalamus (also brain stem, spinal cord, and sympathetic ganglia)
- Temp is lower in AM and highest in PM
- Mechanism:
- Interleukin 1 (IL-1), TNF-a, IL-6, and IFN-gamma are released by monocytes and macrophages in response to inflammatory stimuli (or pathogens).
- These inflammatory mediators stimulate circumventricular organs near the optic chiasm, activing phospholipase A2
- Phospholipase A2 --> (activates) prostaglantin E2 --> (crosses BB barrier) --> ant. hypothalamus + brain stem. --> FEVER
- Fever is beneficial because:
- inhibits growth of viruses, bacteria, fungi, parasites.
- Enhances activity of macrophages, neutrophils, and cell-mediated immune function.
- Fever is harmful because:
- Increases O2 demand:
- Cardiac ischemia.
- COPD exacerbation
- Elderly with limited mental capacity get confusion.
- Child seizures. (no proof that reducing the Temp prevents seizure).
- Increases O2 demand:
- Therefore:
- Beneficial to lower body temp if heart disease, COPD, elderly, etc..
- Use prostaglandin E2 synthesis inhibitors:
- ASA
- (avoid in children- Reye syndrome - hypoglycemic, fatty liver, encephalopathy, renal changes)
- NSAIDs
- Avoid in cardiac - coronary artery vasoconstriction.
- Acetaminophen
- ASA
Fever of Unknown Origin
- Definition:
- Must persist >3weeks. (otherwise may be viral fever that's impossible to prove)
- Fever of >38.3°C on several occasions. (bell curve distribution)
- No Diagnosis after 3 days of testing.
- Differential:
-
Differential:
- "The Big Three"
- Infections
- Neoplasms
- Autoimmune Disese
- "The Little Six"
- Granulomatous Disease
- Regional enteritis
- Familiar Mediterraneal Fever (FMF)
- Drug Fever
- Pulmonary emboli
- Factitions Fever
Diagnostic Tests:
- History/physical guides this!!!
- Go where the money is!
- CBC + diff
- Blood smears - Giemsa and Wright stain
- LFTs
- ANA, Rheumatoid factor
- ESR
- Urinalysis
- Blood, Urine Cultures
- PPD skin test
- Chest and Abdo CT.
- "The Big Three"
- "The Big 3"
- Infections
- Abscesses (abdo)
- Osteomyelitis (bone scan)
- Subacute bacterial endocarditis (blood culture - large volumes, TEE, murmur)
- Biliary Infections
- Subacute pyelonephritis
- Miliary TB
- Leptospirosis (animal or contaminated soil)
- Viruses
- EBV
- CMV
- Neoplasms
- Lymphoma (Hodgkin)
- Leukemia (aleukemic or preleukemic phase)
- Hypernephroma (high sedimation rate)
- Hepatoma
- Atrial Myxoma
- Autoimmune Disease
- Do anti-nuclera and anti-DNA
- Still's Disease
- SLE
- Hypersensitivity angiitis
- Polymyalgia rheumatica + temporal arteritis
- Polyarteritis nodosa
- Mixed connective tissue disease
- Sybacute thyroiditis
- Infections
- "The LIttle Six"
- Granulomatous disease
- Regional enteritis
- Familial Mediterranean Fever (FMF)
- Drug Fever
- Antihistamines, barbiturates, dilantin, Hydralazine, Ibuprophen, Isoniazid, nitrofurantoin, penicillins, procainamide, quinidine, Salicylates, Thiouracil, mercaptopurine.
- Pulmonary Emboli
- Factitions Fever
- Mess with mercury thermometers
- Inject self with feces or saliva (health care worker hx, hiding cyringe)
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- Specific History
- Review of systems
- Past history of infections and family hx.
- Epidemiology, animal exposure, insect bites, travel to developing countries or southwest US or Ohio river valley.
- Medications
- Specific Exam
- Skin for embolic lesions
- Palpate all lymph nodes
- Complete joint exam
- Listen for cardic murmurs
- Abdo exam (liver, spleen, masses/tenderness)
FUO in HIV
- Most common:
- Mycobacterial infections: (Mycobacterial blood culture)
- Mycobacterium tuberculosis
- M. avium intracellulare
- Other atypical mycobacteria
- Other bacterial infections
- CMV (CMV quantitative PCR)
- Pneumocystis
- Toxoplasmosis
- Cryptococcus (Cryptococcal serum antigen)
- Histoplasmosis (hard, if disseminated - Bone marrow culture)
- Mycobacterial infections: (Mycobacterial blood culture)
Fever in ICU (Surgical and Medical)
- Would infection must be excluded
- Look for signs of infection
- Immediate postop period:
- Strep pyogenes --> septic shock and severe bacteremia.
- Later post-op:
- S. aureus + nosocomial pathogens (Pseudomonas, Klebsiella, and E.coli)
- CULTURE + GRAM STAIN
- Empiric Abx: cover G+'s and G-'s.
- Specific cases:
- Intra-abdominal abscess
- need CT
- Intubated (Chest X ray and Blood Gasses)
- Nasopharynx bacteria --> bronchitis/pneumonia
- Sputum sample (>10 neutrophils/HPF and single organism on gram stain)
- CXR and Blood gasses help diff btwn colonization and infection.
- IV catheters (usually multiple
- Line sepsis is common.
- If new fever --> examine all IV and art lines for erythema, warmth, exudate.
- If new fever + shock --> replace all lines, and maybe culture.
- Usually: S. aureus, S. epidermidis
- Use vancomycin (For resistant B-hemolytic strep) + 3rd gen cephalosporin (G-'s)
- If lots of antibiotics
- Worry of Candidemia (esp if 2+ site cultures grown Candida)
- Cover with fluconazole or an echinocandin (caspofungin, anidulafungin, or micafungin)
- Blood culture
- C.difficile colitis
- Worry of Candidemia (esp if 2+ site cultures grown Candida)
- Prolongued bladder catheterization
- Nearly all patients with Foley's develop UTIs in 30days.
- Urinalysis + Urine culture
- NG Tubes.
- Sinusitis + fever
- Need sinus films + abx.
- Non-infectious
- Pulmonary embolus
- Drug Fever (see above)
- Undrained blood collections (let them resorb)
- Intra-abdominal abscess
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